code: def test_output_extractall(test_returns_dataframe):
      """
      Raise ValueError if the output is a dataframe.
      """
      with pytest.raises(ValueError):
          test_returns_dataframe.process_text(
              column_name="text",
              string_function="extractall",
              pat=r"(?P<letter>[ab])?(?P<digit>\d)",
          )
  
imports: import numpy
  import pandas
  import pytest
  from pandas.testing import assert_frame_equal
label_desc: Use image node_id 25 for calling a global function with example usage: test_output_extractall(test_returns_dataframe) without return types